Less Than Old Style Brass Valve. 4AN Default- 6AN or 8AN available on request. Tough And Attractive Powder coated Finish.NX nitrous bottles feature a tough and attractive powdercoated finish. Includes a high flow billet aluminum and back anodized Lightning 45 bottle valve. Wow, how do I start to tell the world why NX is different and better than any other company? NX copies no one; we lead the industry in technology and innovation; Never be satisfied with the status quo; Always give the customer more than he expects!